The present invention refers to a manually operated dispensing device for use with a double dispensing cartridge for two-component compositions. In particular, this invention is related to a device as defined above, comprising a double thrust ram and an advance drive jointly acting upon the double thrust ram and being actuated by a trigger lever, the advance drive comprising a feed element acting on the thrust ram via a toothing of the latter.
Such a device is already commercialized in the form of a small dispensing device wherein the double thrust ram comprises a toothing at its lower surface meshing with a common advance tooth which is fixed to a ratchet and is movable along an arc of a circle. Due to the relatively high specific application pressure, it is necessary to manufacture the thrust ram of a high-quality synthetic material, on one hand, and to use metal parts for the trigger lever and the sole advance tooth or the ratchet, respectively, on the other hand. Thus, the manufacture of the device is expensive and its mounting is time consuming.
The U.S. Pat. No. 5,137,181 of the same applicant discloses several dispensing devices, one of the embodiments described therein shows that the thrust rams are provided on both sides with a toothing, the thrust member comprising ratchets which act upon the toothings. According to one embodiment, the actuating is effected by one thrust tooth each, arranged at both sides of the thrust ram and mounted at the end of a spring loaded thrust tooth holder. The devices disclosed in this document are designed for relatively large cartridges, each one of the thrust rods being provided with driving means.